1. Laboratory of Molecular Entomology and Bee Pathology, Ghent University, 9000 Ghent, Belgium
2. Tigray Agricultural Research Institute, Mekelle P.O. Box 492, Ethiopia
3. Centrum Voor Milieukunde, University of Hasselt, 3590 Diepenbeek, Belgium
4. Holeta Bee Research Center, Holeta P.O. Box 22, Ethiopia